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PubMed1986

Quantitative gas chromatographic analysis of volatile fatty acids in spent culture media and body fluids.

Gas chromatographic analysis of volatile fatty acids for identification of obligately anaerobic bacteria and for presumptive diagnosis of anaerobic infections is now widely practiced. However, it is difficult to compare data because only a qualitative analysis is done or only chromatograms are presented instead of quantitative data on volatile fatty acid production. We compared three stationary phases for volatile fatty acid analysis of aqueous solutions and four methods of pretreating samples for gas chromatography. Quantitative analysis could be done accurately by using Carbowax as the stationary phase after pretreatment of spent culture media with Dowex columns. If only qualitative analysis is required (e.g., for presumptive diagnosis of anaerobic infections), ether extraction and headspace analysis are equally suitable. The overall variation coefficient for volatile fatty acid production by four reference strains of obligately anaerobic bacteria after 24 h of incubation was approximately 10%.

Bacteria, Anaerobic↗
PubMed2000

Role of volatile fatty acids in development of the cecal microflora in broiler chickens during growth.

It is known that volatile fatty acids can inhibit growth of species of the family Enterobacteriaceae in vitro. However, whether these volatile fatty acids affect bacterial populations in the ceca of chickens is unknown. Therefore, a study was conducted to investigate if changes in volatile fatty acids in ceca of broiler chickens during growth affect bacterial populations. Results showed that members of the Enterobacteriaceae and enterococci are present in large numbers in 3-day-old broilers and start to decrease when broilers grow older. Lactobacilli are present in large numbers as well in 3-day-old broilers, but they remain stable during the growth of broilers. Acetate, butyrate, and propionate increase from undetectable levels in 1-day-old broilers to high concentrations in 15-day-old broilers, after which they stabilize. Significant negative correlations could be calculated between numbers of Enterobacteriaceae and concentrations of undissociated acetate, propionate, and butyrate. Furthermore, pure cultures of Enterobacteriaceae isolated from the ceca were grown in the presence of volatile fatty acids. Growth rates and maximal optical density decreased when these strains grew in the presence of increasing volatile fatty acid concentrations. It is concluded that volatile fatty acids are responsible for the reduction in numbers of Enterobacteriaceae in the ceca of broiler chickens during growth.

Animals↗
PubMed1979

Volatile fatty acids and aerobic flora in the gastrointestinal tract of mice under various conditions.

Volatile fatty acids are reported to exert a repressive effect upon Enterobacteriaceae and Pseudomonas species in vitro and in vivo in young mice. The mean total volatile fatty acid concentration in the cecal samples of conventional mice fed ad libitum was 81.7 mumol/g (wet weight), which is antibacterial in vitro, and in the rectal samples it was 41.1 mumol/g (wet weight). The mean count of Enterobacteriaceae in the cecum was only 10(2)/g, whereas in the rectum it was 10(5)/g. Volatile fatty acid levels were influenced by food intake and increased to peak levels approximately 6 to 10 h after eating and then declined. In mice fasted for 17 h, the butyric acid concentration was considerably lower and the number of cecal samples positive for Enterobacteriaceae increased. When fasted for 4 days, mice had extremely low cecal and rectal volatile fatty acid concentrations and the Enterobacteriaceae and enterococci counts increased to mean of 2 x 10(6)/g and 3 x 10(6)/g, respectively, in the cecum and to means of 10(7) and 5 x 10(6)/g in the rectum. We conclude that volatile fatty acids are probably one of the many interference mechanisms which are involved with control of the levels of Enterobacteriaceae (and enterococci) in the large intestine of mice.

Aerobiosis↗
PubMed1985

Net portal absorption of lactate and volatile fatty acids in steers experiencing glucose-induced acidosis or fed a 70% concentrate diet ad libitum.

Five crossbred steers (347 kg) were surgically fitted with rumen fistulae, hepatic portal, abdominal aorta and mesenteric catheters to measure organic acid absorption from the gut during acute [intraruminal glucose, 12 g/kg body weight (G)] or subacute [ad libitum 70% concentrate diet (C)] acidosis. Samples were taken at time 0, then every 2 h for 48 h after a switch from an alfalfa diet to C, or dosing with G. Steers receiving C received G 1 wk later so that five steers provided four observations/treatment. Blood flow rates were determined by infusion of para-amino hippuric acid (PAH) and averaged 767.8 and 712.5 liters/h for C and G, respectively. Animals consuming C averaged 13.6 kg dry matter from 0 to 24 h and 1.5 kg from 24 to 48 h. Rumen pH declined to 4.2 for G compared with 6.0 for C. Blood pH and HCO3 showed only slight depressions for G from 16 to 26 h, the period of lowest rumen pH. Rumen L-lactate concentration averaged 53.4 mM (peak 77 mM) and 2.1 mM for G and C, respectively. Rumen D-lactate concentration averaged 30.2 mM (peak 47 mM) for G and 1.2 mM for C. Net portal absorption of L-lactate averaged 96.6 and 164.4 mmol/h, whereas that of D-lactate averaged 10.5 and 71.8 mmol/h for C and G, respectively. Mean net portal volatile fatty acid absorptions were 442.8, 192.1, 53.8, 5.3 and 10.4 mmol/h (C) and 100.0, 47.2, 9.4, .98 and .78 mmol/h (G) for acetate, propionate, butyrate, isobutyrate and isovalerate, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗
PubMed2002

Fermentation of municipal primary sludge: effect of SRT and solids concentration on volatile fatty acid production.

Laboratory bench-scale experiments were conducted to investigate the performance of primary sludge fermentation for volatile fatty acids production. Primary sludges from two major wastewater treatment plants located in Valencia (Pinedo and Carraixet) were used. Experiments were performed at solids retention times between 4 and 10 days, and total volatile solids concentrations between 0.6% and 2.8%. Operation at two temperatures (20 degrees C and 30 degrees C) was also checked. Results indicated the importance of feed sludge characteristics on volatile fatty acids yields, being approximately double for the Carraixet wastewater treatment plant sludge than for the Pinedo plant. In both cases, higher volatile fatty acids yields were observed at higher total volatile solids concentrations. Solids retention times above 6 days scarcely improve volatile fatty acids yields, while experiments conducted at 4 days of solids retention times show an important decrease in volatile fatty acids yields. On raising temperature an increase in volatile fatty acids yields was observed, mainly due to an improvement in the hydrolysis of particulate organic matter.

Bioreactors↗
PubMed1987

Protein origin of the volatile fatty acids isobutyrate and isovalerate in human stool.

Normal human stool contains five commonly recognized volatile fatty acids, of which three (acetate, propionate, and butyrate) are the product of carbohydrate degradation. We investigated whether the remaining two volatile fatty acids, isobutyrate and isovalerate, are produced by degradation of amino acids. Stools from six healthy subjects were incubated with albumin, valine, leucine, tryptophan, phenylalanine, glucose, or sucrose under atmospheres containing oxygen in the range of 0% to 5%. Isobutyrate was produced only from albumin and valine, and isovalerate was produced only from albumin and leucine. Glucose- and sucrose-containing incubates produced only acetate, propionate, and butyrate. The rate of production for each of the volatile fatty acids was constant over the various oxygen concentrations tested. We conclude that isobutyrate and isovalerate in stool are formed from valine and leucine degradation respectively. Quantitation of individual fecal volatile fatty acid excretions may reflect intracolonic degradation of protein and carbohydrate.

Albumins↗
PubMed1986

Volatile fatty acid findings in vaginal fluid compared with symptoms, signs, other laboratory results, and susceptibility to tinidazole of malodorous vaginal discharges.

The relevance of volatile fatty acids as a diagnostic test in 79 women with abnormal vaginal discharge was evaluated by a blind, randomised, and placebo controlled trial of tinidazole as a single oral 2 g dose. Automated gas chromatography of ether extracts of discharges taken before treatment showed volatile fatty acids in 18. Volatile fatty acids correlated with malodorous, colour, and microscopically assessed altered bacterial flora and clue cells. At follow up one week later, the odour, colour, and volatile fatty acids in the vaginal discharge of women treated with tinidazole had become normal more often than in those receiving placebo. The disappearance of volatile fatty acids correlated with clinically assessed improvement in women treated with tinidazole. The volatile fatty acid test as an indicator of anaerobic bacterial flora is objective, technically simple and fast, has few problems of sample size and transportation, and may be useful in the aetiological classification and follow up treatment of non-specific vaginal discharges.

Body Fluids↗
PubMed2002

Application of membrane-coupled anaerobic volatile fatty acids fermentor for dissolved organics recovery from coagulated raw sludge.

To investigate the treatment performance of membrane-coupled anaerobic volatile fatty acids fermentor system, the effects of operational parameters for volatile fatty acids production were evaluated through experiments and a mathematical model. The volatile fatty acids recovery ratio was largely affected by the change of hydraulic retention time, reaching its maximum value at 12 hrs. Over the range of hydraulic retention time 8 to 96 hrs, the volatile fatty acids recovery ratio decreased with the increase of hydraulic retention time above 12 hrs, while the ratio of mineralization and gasification increased. Hydraulic retention time and membrane filtration ratio should be maintained less than 1 day and above 0.9, respectively, to attain over 40% of organic materials recovery ratio at 10 days of solids retention time. When the hydrolysis rate constant was 0.01 hr-1, the organic loading rate should be maintained at above 1.0 (kgC/m3/day) to attain over 45% of volatile fatty acids recovery ratio. Based on experimental and simulated results, membrane-coupled anaerobic volatile fatty acids fermentor system was thought to be effective for dissolved organics recovery from coagulated sewage sludge.

Bacteria, Anaerobic↗
PubMed2000

Gastrointestinal volatile fatty acid concentrations and pH in cats.

OBJECTIVE: To measure volatile fatty acid (VFA) concentrations and pH in the gastrointestinal tracts of healthy adult cats fed a commercial dry cat food. ANIMALS: 14 cats. PROCEDURE: The gastrointestinal tracts were excised immediately after euthanasia and divided into 6 sections (stomach, duodenum, jejunum, ileum, proximal portion of the colon, and distal portion of the colon). Luminal contents were collected from each segment, pH was measured, and contents were centrifuged. The supernatant was analyzed for acetate, proprionate, butyrate, isobutyrate, valerate, and isovalerate concentrations by use of gas chromatography. RESULTS: Mean total VFA concentrations were lowest in the stomach (20 mmol/L); increased through the duodenum, jejunum, and ileum (30, 29, and 41 mmol/L, respectively); and were greatest in the proximal and distal portions of the colon (109 and 131 mmol/L, respectively). Estimated mean total VFA amounts were low (<600 micromol) throughout all segments of the gastrointestinal tract; pH values increased from the stomach through the ileum and subsequently decreased in the colon. CONCLUSIONS AND CLINICAL RELEVANCE: Total VFA concentrations in the colon were comparable to values reported for the forestomach of ruminants and large intestines of monogastric animals, whereas values in the small intestine were higher than reported for other species. Total VFA amounts were low, consistent with the short, nonvoluminous gastrointestinal tract of carnivores. Luminal pH varied throughout the gastrointestinal tract in a pattern similar to other monogastric animals. Volatile fatty acids probably contribute minimal metabolic energy in cats but may be important in the maintenance of local mucosal health.

Animals↗
PubMed1983

Excess rumen product anions in cattle. I. Blood clearance rates and reduced liver function from sublethal doses of volatile fatty acids, lactate and succinate.

Blood clearance rates of volatile fatty acids, lactate and succinate were estimated in cattle following a single rapid intravenous injection of a Na-anion solution. Bromosulfophthalein was administered immediately before the anion to monitor the effects upon liver function, blood circulation, and dose equilibrium. Acetate, propionate, and valerate at doses up to 5 mmole/kg were cleared quickly from the blood by a first-order process without effects either upon the animal or bromosulfophthalein clearance. Injection of acetic acid solutions produced no effects. Butyrate was toxic at doses above 1 mmole/kg and progressively affected both the rate and progress of bromosulfophthalein clearance as the dose increased. Lactate and succinate were toxic and lethal at doses around 0.25 mmole/kg, and caused both reduced rates and altered progress of bromosulfophthalein clearance. The toxic reactions resulted in total collapse from loss of muscle tone. The butyrate and lactate effects were accentuated when the anion solutions were injected at low pH where a large portion of the anion would be unionized. Levels of butyrate, lactate and succinate in the rumens of feedlot cattle were high enough to provide toxic doses of these anions. The results are discussed in terms of the effects of excess rumen production of these anions upon the liver function and health of feedlot cattle.

Animals↗
PubMed2005

[Analysis of volatile fatty acids in gingival crevicular fluid of patients with chronic periodontitis].

OBJECTIVE: To investigate the volatile fatty acids in gingival crevicular fluid (GCF) and to analyze the relationship between the levels of the volatile fatty acids and chronic periodontitis. METHODS: GCF samples taken from 37 patients with chronic periodontitis and 16 volunteers with healthy periodontal status were analyzed by capillary electrophoresis. RESULTS: The detection frequencies and concentrations of succinic acid, butyric acid and valeric acid were significantly higher in GCF of chronic periodontitis than in that of healthy group. The detection frequencies of propionic acid had no statistic difference between the two groups, but the concentrations of it was significantly higher in inflammation group. We also found that the concentrations of succinic acid, propionic acid and butyric acid were significantly lower in shallow pockets than that in deep pockets. CONCLUSIONS: The volatile fatty acids, especially succinic acid, propionic acid, butyric acid and valeric acid were associated significantly with the severity and inflammation of periodontal disease. The levels of succinic acid, propionic acid and butyric acid in GCF were related to pocket depth.

Adult↗
PubMed1981

Partial purification of enzymes of bovine kidney mitochondria activating volatile fatty acids.

Mitochondria were prepared from kidney cortex tissue of lactating Holstein cows, and enzymes activating volatile fatty acids partially purified. Two fractions activating volatile fatty acids were obtained; one was similar to components isolated from bovine heart mitochondria activating acetate and propionate (acetyl CoA synthetase). The other was similar to components of bovine liver mitochondria and activated propionate, butyrate, and valerate but not acetate. On calcium phosphate gel chromatography this latter fraction could be separated into a distinct propionyl CoA synthetase (Michaelis-Menten constant for propionate 2.54 x 10(-3)M) and a fraction activating butyrate and valerate. The role of a distinct propionyl CoA synthetase in kidney mitochondria remains to be elucidated because propionate is not a major substrate in peripheral blood of ruminants. We concluded that volatile fatty acid activation by bovine kidney mitochondria is due to an acetyl CoA synthetase, a propionyl CoA synthetase, and a butyrate and valerate-activating fraction probably composed of separate butyryl and valeryl CoA synthetases.

Acetate-CoA Ligase↗
PubMed2003

Volatile fatty acids as malodorous compounds in wool scouring water and lanolin. Origin and characterisation.

Volatile fatty acids (C2-C7) analysis in wool scouring water and lanolin is presented. These substances are of major interest as malodorous compounds in urban and industrial wastewaters. In this work, they have been analysed in wool scouring water by headspace solid-phase microextraction followed by gas chromatography negative chemical ionisation mass spectrometry. Most of the volatile fatty acids have been identified at microg g(-1) levels. In addition, since lanolin is a major impurity of raw wool, volatile fatty acid patterns of wool scouring water and lanolin have been compared in order to establish the origin of these compounds in the wastewater. Finally, the efficiency of the deodorization step, mandatory to obtain commercial lanolin, has been assessed taking into account the decrease in volatile fatty acid content from the raw wool to the lanolin.

Animals↗
PubMedDate not supplied

[Characteristics of the methane fermentation of waste of animal husbandry complexes with respect to the biomass of microorganisms and volatile fatty acids].

The content of microbial biomass and the concentration of volatile fatty acids were comparatively studied in the tanks where the waste products of three stock farms were subjected to methane fermentation. The biomass content was shown to vary from 19 to 30% of the dry matter weight and the concentration of volatile fatty acids from 0 to 4.5 g per litre. The low concentrations of acetic and propionic acids together with the high biomass content were indicative of an active balanced microbial association. The parameters can be used to assess the operation of methane fermentation tanks.

Animal Husbandry↗